Makes sense. Nobody wants to deal with "this user-agent claims to support TLS 1.2, except this extension that was added in 2026" anymore.

If you're going to add or remove features, follow semver and bump that number.

This isn't quite how TLS feature negotiation works.

Version numbers are negotiated and some of the parameters are carried along with the version, but a lot of functionality (e.g., cipher suites) is individually negotiated and to some extent orthogonal to the version. This of course also allows you to add new features to an existing version.

What this draft is saying is that the IETF will not be adding new features targeted at TLS 1.2.